1. Technical Field
The present disclosure relates to a transmission apparatus and a transmission method.
2. Description of the Related Art
A communication method called Multiple-Input Multiple-Output (MIMO), for example, is known as a communication method using multiple antennas. In multi-antenna communication for a single user represented by MIMO, multiple sequences of transmission data are individually modulated, modulated signals obtained accordingly are simultaneously transmitted from different antennas, and thus the data communication speed is increased.
FIG. 33 is a diagram illustrating an example of the configuration of a transmission apparatus that is based on the Digital Video Broadcasting-Next Generation Handheld (DVB-NGH) standard in a case where the number of transmission antennas is two and the number of modulated transmission signals (transmission streams) is two, which is described in “MIMO for DVB-NGH, the next generation mobile TV broadcasting,” IEEE Commun. Mag., vol. 57, no. 7, pp. 130-137, July 2013. In the transmission apparatus, data 1 is input and coded by an encoder 2 to obtain data 3, which is divided into data 5A and data 5B by a distributer 4. The data 5A is subjected to interleaving processing performed by an interleaver 4A and mapping processing performed by a mapper 6A. Likewise, the data 5B is subjected to interleaving processing performed by an interleaver 4B and mapping process performed by a mapper 6B. The coding processing in the encoder 2, the interleaving processing in the interleavers 4A and 4B, and the mapping processing in the mappers 6A and 6B are performed on the basis of setting information included in a frame configuration signal 13.
Weight combiners 8A and 8B receive mapped signals 7A and 7B and perform weight combining thereon to generate weight combined signals 9A and 16B, respectively. After that, the weight combined signal 16B is subjected to phase change performed by a phase changer 17B, and a phase-changed signal 9B is output. Subsequently, radio sections 10A and 10B perform, for example, processing related to orthogonal frequency division multiplexing (OFDM), such as frequency conversion and amplification. In addition, a transmission signal 11A is transmitted from an antenna 12A, and a transmission signal 11B is transmitted from an antenna 12B. The weight combining processing in the weight combiners 8A and 8B and the phase change processing in the phase changer 17B are performed on the basis of signal processing method information 115 generated by a signal processing method information generator 114. The signal processing method information generator 114 generates the signal processing method information 115 on the basis of the frame configuration signal 13. At this time, in the phase changer 17B, for example, nine phase change values are provided and phase change in a period of 9 is regularly performed.
Accordingly, there is a high possibility of being able to avoid a situation where a reception apparatus as a communication partner falls into a steadily poor reception state in an environment in which direct waves are dominant. Accordingly, it is possible to improve the data reception quality at the reception apparatus as a communication partner.